The prior art is generally cognizant of conventional window coverings in which a roll of material is mounted at the top of the window so that the material may be unrolled and pulled down to cover the window. When the purpose of the window covering simply is to exclude a part of the light passing through the window, it is customary to make no attempt to seal or secure the window covering to the window or to the window frame. When an attempt is made to more completely seal the window, various structures have been utilized to contact and secure the vertical edges of the window covering.
Typical of the prior art is Smith, U.S. Pat. No. 1,142,918, in which a structure is provided to secure the edges of a rollable screen for the prevention of the passage of insects. The screen is stiffened with horizontally disposed metal rods having knobs at their ends. The knobs and the vertical edges of the screen slide downwardly through a rigid, metal track adapted to guide the edge of the screen and to retain the knobs, sealing the screen within the track. Kaletay, U.S. Pat. No. 2,084,847, provides a rigid track adapted to be squeezed down upon the edges of a rollable window insect screen. The screen is first pulled down into place, passing along a vertical, metal slot, and then a lever and cam device is used to squeeze the opposing parts of the slot together to grasp the screen. In Morse, U.S. Pat. No. 2,548,041, a spring-loaded, rigid hinge member is adapted to press the edges of material drawn over the window against an opposing metal surface, again to create a clamping effect.
Helgoth, U.S. Pat. No. 2,314,784, and Spencer, U.S. Pat. No. 2,564,770 both show elastic strips of metal or other suitable material adapted to press the vertical edges of window shades against a part of the frame of the window, so as to seal or secure them. Klaenhammer et al., U.S. Pat. No. 4,079,772, provides for the sealing of the sides and bottom of the window shade by the securing of a magnetized strip to the window frame and a corresponding ferromagnetic sealing strip to the shade. Moriarty et al., U.S. Pat. No. 4,126,174, shows a flexible sheet, roll up window covering having a vertical rib along each side of the sheet. The rib is guided between and held by opposed surfaces of a rigid seal guide strip mounted to the window frame. A transverse sealing pad extends across the top of the window frame and contacts the sheet material used to cover the window so as to provide a seal therebetween.
The window shade sealing mechanisms of the prior art require relatively long, rigid members that are inconvenient to ship or store during the marketing of such devices. Furthermore, complicated and relatively expensive fabrication often must be employed to make the extruded or folded metal and plastic parts utilized to guide or grasp the sides of a window covering. A facility with tools, and especially with saws or other means for cutting rigid materials is required in the installer of the prior art devices, who most cut various channels and guides made from such materials to fit the size of the window to be sealed. Alternatively, the provider of such materials must keep a wide variety of sizes in stock. In addition, with many of the prior art structures, the exact size and especially the width of the window covering is critical to the successful operation of the sealing device. Similarly, the size of the top sealing pad of Moriarty is critical to the success of the device shown.